Entry doors, patio doors, and the like generally include a pair of spaced vertical side jambs, a head jamb or header extending between the upper ends of the side jambs, and a door sill extending between the bottom ends of the side jambs. Hinged or sliding door panels are mounted within the resulting frame and, when closed, directly overly a threshold portion along the inside of the sill. Many hinged entry doors open into a building in which they are mounted and thus are know as in-swing doors. A variety of sill configurations are available for use with entry doors including wooden sills, aluminum sills, plastic sills, composite sills, and the like.
One type of sill used for entry doors is known as a “contain-and-drain” sill. In general, a contain-and-drain sill typically is extruded from plastic or a composite material and is generally hollow inside with, perhaps, some longitudinal support ribs, which form chambers inside the sill. Openings are formed in the support ribs communicating between adjacent chambers. The ends of the sill are sealed with an end cap and one or more weep holes, which may be provided with weep doors or flaps, are formed along the outside nosing of the sill communicating between its hollow interior and the outside.
Under various conditions, water can collect on the threshold portion of the sill beneath a closed door. For example, rainwater can leak past the weather seals or snow from shoes can be deposited on the sill and melt. In order to manage this water, it is known to provide one or more drains in the threshold portion of the sill through which water can drain into the hollow interior of the sill. Once contained within the interior of the sill, the water can drain out of the sill through the weep holes formed along its outside nosing. Such drains also function as vents that help to equalize pressure differentials between the outside of a doorway and the inside of a building and vent air displaced by rising water in the sill.
A major problem with contain-and-drain sills can arise when it rains in high wind conditions, i.e. when the doorway is under high “DP” loads. The high winds can raise the air pressure on the exterior of a doorway relative to the interior of the doorway, thus creating a partial vacuum within the hollow interior of the sill. As used herein, the term “partial vacuum” means that there exists a negative pressure differential between the outside of the doorway and the hollow interior of the door sill. The partial vacuum, in conjunction with rain water that tends to build up around the sill, can cause air and water to be sucked through the weep holes into the interior of the sill, which can begin to fill with water and bubbles. The water generally rises until the head of water within the sill equals the pressure differential between the outside and inside of the doorway.
As the water level rises within the sill, the air that is displaced by the water, as well as air being sucked into the sill by the partial vacuum, must escape the sill and generally does so through the drains in the threshold portion of the sill. Often, and particularly in driving rains, there is collected water in the threshold portion, which is draining into the interior of the sill through the drains. The simultaneously escaping air through these drains causes percolation and bubbling of the water at the locations of the drains. Even when there is no collected water on the threshold portion of the sill, percolation and bubbling can still occur as a result of bubbles that develop within the sill due to the mixture of water and air being sucked in.
Bubbling and percolation at the drains can result in water leakage into a dwelling, which can cause damage and can cause a doorway to fail to meet building standards for water resistance. It has been known to add vents up the side jambs or in some other remote area of the door unit through which air in the sill can escape. However, it is not always possible to vent to a remote location and, when it is not, venting commonly occurs through the drains resulting in bubbling. Even when air is vented remotely, the result may not always be completely satisfactory.
A need therefore exists for a doorway with a contain-and-drain sill that effectively contains and allows water to rise within the sill under high wind load conditions without percolation and bubbling of the water and air at drain locations. A further need exists for such a doorway that drains water effectively into the interior of the sill from the threshold portion of the sill without percolation or bubbling occurring at the drain site. It is to the provision of such a doorway that the present invention is primarily directed.